All-in-one Collaborative API Development Platform

API Design

API Documentation

API Debugging

API Mock

API Automated Testing

Sign up for free

Test Cases for API Testing with Example

Start for free
Home / Basic Knowledge / Test Cases for API Testing with Example

Test Cases for API Testing with Example

As APIs grow in usage and complexity, properly testing them is crucial for delivering high-quality applications. This article will explore API testing and provide examples of effective API test cases.

Application Programming Interfaces (APIs) have become ubiquitous in software development. APIs allow different applications to communicate with each other by exposing functionality and data.

As APIs grow in usage and complexity, properly testing them is crucial for delivering high-quality applications. This article will explore API testing and provide examples of effective API test cases.

Apidog's automation testing simplifies API test case management. The "Test Scenario" feature enables users to capture and quickly rerun test scenarios with saved parameters. Apidog supports multiple instances within a scenario for diverse runtime needs, along with test data set configurations and integration with third-party notification channels for CI test runs.

What is API Testing?

API testing is a type of software testing that involves testing application programming interfaces (APIs) directly and as part of integration testing across applications. An API is a communication interface that allows different software components or applications to interact with each other and exchange data.

The most common strategies of API testing include:

  1. Functional Testing: Verifying that the API is behaving as expected and delivering the correct responses for different input scenarios.
  2. Reliability Testing: Ensuring that the API can handle different load conditions, large volumes of data, and various stress scenarios without crashing or becoming unresponsive.
  3. Security Testing: Identifying potential security vulnerabilities in the API, such as authentication and authorization issues, injection flaws, or data exposure.
  4. Performance Testing: Measuring the API's performance characteristics, such as response times, throughput, and resource utilization under different load conditions.
  5. Validation Testing: Verifying that the API adheres to specified standards, protocols, and data formats, ensuring compatibility with different clients or consumers.

What are Test Cases for API Testing?

A test case refers to a predefined set of actions, inputs, and expected results aimed at evaluating the functionality and robustness of a software system. Testers meticulously outline the steps to execute, specify input data, and define anticipated outcomes to validate whether the software operates as desired.

Documentation of test cases commonly occurs in a specialized testing document, such as Google Sheets or a text document, or within a dedicated test case management tool like Apidog, TestRail, Zephyr, qTest, or PractiTest. In automated testing contexts, test cases are often scripted directly within code files utilizing programming languages and testing frameworks.

API testing is exposed by applications and services. While manual debugging and verification of numerous APIs can be impractical and time-consuming, automated testing significantly enhances efficiency by freeing developers from manual tasks. Test cases play a pivotal role in automating the testing process, enabling the resolution of complex scenarios swiftly and effectively.

Why You Need an API Test Case Template?

A test case template is necessary for standardizing, clarifying, and efficiently documenting test cases. A test case template is essential for several reasons:

  1. Standardization: It provides a standardized format for documenting test cases, ensuring consistency across the testing process. This consistency aids in better understanding, communication, and collaboration among team members.
  2. Clarity: A template clearly outlines the necessary information for each test case, such as test steps, expected results, preconditions, and postconditions. This clarity helps testers understand what needs to be tested and how to conduct the tests effectively.
  3. Efficiency: Using a template saves time by eliminating the need to create test case documentation from scratch for each test scenario. Testers can focus more on testing activities rather than spending time on documentation.
  4. Reusability: Test case templates can be reused for similar test scenarios or future testing cycles, reducing duplication of effort and promoting efficiency in test case creation.
  5. Traceability: Test case templates facilitate traceability between requirements, test cases, and defects. By documenting the relationship between test cases and requirements, it becomes easier to ensure that all requirements are adequately tested and that any defects found are properly addressed.
  6. Quality Assurance: Test case templates promote thoroughness and completeness in test case design. They ensure that all aspects of the software application are tested, leading to higher quality and reliability of the final product.

How to Write Test Cases for API Testing

Writing test cases for API testing is an important step to ensure comprehensive and effective testing of the API functionality. Here are some best practices and steps to follow when writing test cases for API testing:

  1. Understand the API Specification: Review the API documentation, request/response formats, data structures, and expected behaviors thoroughly. This will help you identify the test scenarios and test data required for testing.
  2. Identify Test Scenanrios: Based on the API specification, identify the different test scenarios that need to be covered. These may include:
  • Positive test cases: Testing the API with valid inputs and verifying the expected responses.
  • Negative test cases: Testing the API with invalid inputs or boundary conditions to verify error handling and response codes.
  • Functional test cases: Testing the core functionality and business logic of the API.
  • Non-functional test cases: Testing performance, security, reliability, and other non-functional requirements.

3. Define Test Data: Prepare the test data required for each test case. This may include valid and invalid input data, edge cases, and different data formats or structures.

4. Write Test Cases: For each test scenario, write detailed test cases that include the following information:

  • Test Case ID: A unique identifier for the test case.
  • Test Case Description: A brief description of the test case scenario.
  • Prerequisites: Any prerequisites or setup required before executing the test case.
  • Test Steps: Detailed steps to execute the test case, including the API endpoint, request method (GET, POST, PUT, DELETE), request headers, request body (if applicable), and expected response.
  • Test Data: The specific test data to be used for the test case.
  • Expected Result: The expected response from the API, including response codes, response headers, and response body.

5. Use a Test Case Management Tool: Consider using a test case management tool or a spreadsheet to organize and maintain your test cases. Apidog is a good choice for you. This will make it easier to track, update, and execute test cases during the testing process.

6. Include Automation Scripts:  If you plan to automate the API testing process, include the automation scripts or references to the automation code in your test cases. This will help ensure traceability between the test cases and the automated tests.

7. Review and Update: Regularly review and update your test cases as the API evolves or new requirements are introduced. Ensure that your test cases remain relevant and cover all the necessary scenarios.

API Test Case Template Component

No matter what method to document the test case was chosen, we should include the following fields in the test case:

Field Description
Test Case ID Unique identifier for the test case.
Title/Description Concise description of the test case's purpose.
Test Objective Specific goal or objective of the test.
Preconditions Necessary conditions required before executing the test.
Test Steps Step-by-step sequence of actions during the test.
Input Data Data or parameters used as test inputs.
Expected Results Anticipated outcomes after executing the test steps.
Actual Results Observed outcomes during test execution.
Test Environment Details about system, hardware, software, and configurations.
Test Data Preparation Instructions for setting up required test data.
Test Execution Date Date and time of test execution.
Test Execution Status Pass/fail status of the test case.
Test Conclusion Summary of test results and observations.
Test Verdict Judgment on the overall success of the test.
Bug Details (optional) Information about identified defects, severity, and steps to reproduce.
Attachments Relevant files, screenshots, or documentation.
Test Case Author Person responsible for creating the test case.
Test Case Reviewer Person who reviewed and approved the test case.
Test Case Version Version or revision number of the test case.
Notes/Comments Additional insights or comments related to the test case.

Example: Writing a Test Case for API Testing in Apidog

To conduct automated testing efficiently, utilizing API testing tools is essential. Previously, without such tools, automated testing necessitated manual scripting and test case creation, which was both time-consuming and labor-intensive. However, with solutions like Apidog, the process is significantly streamlined.


Apidog not only facilitates test case management and automated testing but also offers mock services, enabling testers to simulate API behavior for better testing and debugging. Its intuitive interface empowers testers to swiftly create, edit, and execute test cases, while its robust automation capabilities enable the rapid execution of numerous test cases, accompanied by detailed test reports.

Additionally, Apidog promotes efficient test management, aids in organizing test cases, and fosters seamless team collaboration, allowing testers to share test cases and results effectively, thereby enhancing overall testing productivity and effectiveness.


After opening Apidog, go to 'Testing' > click '+' > select directory and priority to create a New Test Scenario.

Create a New Test Scenario

After entering the test scenario, click "Add Step" and add an API. And you can also import your API test cases into Apidog for automated testing.

Add a Testing Step

With Apidog, anyone can start testing APIs faster and integrate automated testing into their workflows for reliable, efficient testing.


In conclusion, API testing is vital for software quality, and effective test cases are essential. Apidog simplifies API testing with intuitive management, automation, and detailed reporting. We recommend Apidog for streamlined and efficient API testing.